FULL-WAVE ANALYSIS OF RADIATION EFFECT OF MICROSTRIP TRANSMISSION-LINES

A full-wave analysis of radiation effects produced by discontinuities in microstrip and buried microstrip transmission lines is presented. B eginning with the dyadic Green's function for a dielectric slab, with an embedded source, an integral equation is formulated. This equation is then solved by the method of moments to obtain the current distribu tions along the transmission line, in particular, near the discontinui ties. Employing these results, the near- and far-zone fields, as well as radiation patterns are computed. The results from our method showed good agreement with those of previous publications in complex reflect ion and transmission coefficients, and equivalent capacitance values. It is found that under resonance conditions the radiation efficiency o f a simple structure can exceed 41 %, which may cause a potential prob lem in electromagnetic compatibility. Our analytic result also shows t hat the maximum radiation occurs when the source is located at the hei ght of lambda0/4 square-root epsilon(r) from the bottom ground plane, which should be prevented.